Neue Beobachtungen zur Bestäubung vonOphrys (Orchidaceae) in Südspanien,mit besonderer Berücksichtigung des FormenkreisesOphrys fusca agg.

An investigation of pseudocopulation behaviour in species ofOphrys from southern Spain confirms the close relationship betweenCampsoscolia ciliata (Scoliidae) andOphrys speculum, and betweenEucera nigrilabris (Apoidea) andOphrys tenthredinifera. It could be demonstrated thatEucera barbiventris is the pollinator ofOphrys scolopax subsp.scolopax, whereas other species ofEucera andTetralonia which are active at the same time show no interest at all for the flowers of this species. Special attention was paid to the forms of the taxonomically confusedOphrys fusca group:O. fusca s. str.,O. iricolor, O. omegaifera andO. atlantica. WhileO. fusca s. str. is widespread, small-flowered and has late anthesis,O. iricolor has very large flowers and early anthesis. Each of the four members ofO. fusca agg. in S. Spain is pollinated by a different bee, and selective experiments show that each of these four species of bees is specifically attracted only to one of theOphrys species:Andrena flavipes is the pollinator ofO. fusca s. str.,Colletes cunicularius infuscatus ofO. iricolor, Anthophora atroalba ofO. omegaifera, andChalicodoma parietina ofO. atlantica. These four pollinators belong to 4 different bee families (Andrenidae, Colletidae, Anthophoridae, Megachilidae). As this type of pollination represents a very effective pregamic isolation mechanism, these four taxa ofOphrys fusca agg., at least in southern Spain, behave and should be regarded as genuine species.

     

Spatio‐temporal genetic structure and the effects of long‐term fishing in two partially sympatric offshore demersal fishes

Environmental gradients have been shown to disrupt gene flow in marine species, yet their influence in structuring populations at depth remains poorly understood. The Cape hakes (Merluccius paradoxus and M. capensis) are demersal species co‐occurring in the Benguela Current system, where decades of intense fishing resulted in severely depleted stocks in the past. Previous studies identified conflicting mtDNA genetic substructuring patterns and thus contrasting evolutionary trajectories for both species. Using 10 microsatellite loci, the control region of mtDNA and employing a seascape genetics approach, we investigated genetic connectivity and the impact of prolonged exploitation in the two species, which are characterized by different patterns of fishing pressure. Three consecutive years were sampled covering the entire distribution (N = 2100 fishes). Despite large estimated population sizes, both species exhibited low levels of contemporary genetic diversity (0.581 < H_E < 0.692), implying that fishing has had a significant impact on their genetic composition and evolutionary trajectories. Further, for M. paradoxus, significant temporal, but not spatial, divergence points to the presence of genetic chaotic patchiness. In contrast, M. capensis exhibited a clear latitudinal cline in genetic differentiation between Namibia and South Africa (F_ST = 0.063, P < 0.05), with low (0.2% per generation) estimates of contemporary gene flow. Seascape analyses reveal an association with bathymetry and upwelling events, suggesting that adaptation to local environmental conditions may drive genetic differentiation in M. capensis. Importantly, our results highlight the need for temporal sampling in disentangling the complex factors that impact population divergence in marine fishes.     

Induction of sporulation in Bacillus brevis. 2. Dependence on the presence of the peptide antibiotics tyrocidine and linear gramicidin

This paper presents evidence that the two peptide antibiotics tyrocidine and linear gramicidin, produced by Bacillus brevis ATCC 8185, are required for the induction of sporulation in the producer organism. When tyrocidine synthesis was specifically blocked with 2-amino-3-hydroxy-3-phenylpropanoic acid [Mach, B., Reich, E., and Tatum, E. L. (1963) Proc. Natl Acad. Sci. USA, 50, 175-181], sporulation and gramicidin synthesis were inhibited, but both processes could be restored by the addition of tyrocidine. Certain other amino acids such as L-tyrosine inhibited both sporulation and peptide antibiotic synthesis in nitrogen-limited cultures. When either tyrocidine or linear gramicidin was added together with L-tyrosine, neither sporulation nor peptide antibiotic synthesis was restored. On the other hand, the addition of both tyrocidine and linear gramicidin effectively reversed the inhibition of sporulation by L-tyrosine. These experiments demonstrate that sporulation of B. brevis depends on either the endogenous synthesis or the addition of both tyrocidine and linear gramicidin. The fact that endogenous as well as exogenous peptides could effect sporulation argues against the involvement of artifacts, such as the depletion of intracellular nucleotide pools caused by the surfactant properties of added peptide antibiotics.     

Adherence to prescribed antihypertensive drug treatments: longitudinal study of electronically compiled dosing histories

Objective To describe characteristics of dosing history in patients prescribed a once a day antihypertensive medication.Design Longitudinal database study.Setting Clinical studies archived in database for 1989-2006.Participants Patients who participated in the studies whose dosing histories were available through electronic monitoring.Main outcome measures Persistence with prescribed antihypertensive treatment and execution of their once a day drug dosing regimens.Results The database contained dosing histories of 4783 patients with hypertension. The data came from 21 phase IV clinical studies, with lengths ranging from 30 to 330 days and involving 43 different antihypertensive drugs, including angiotensin II receptor blockers (n=2088), calcium channel blockers (n=937), angiotensin converting enzyme inhibitors (n=665), β blockers (n=195), and diuretics (n=155). About half of the patients who were prescribed an antihypertensive drug had stopped taking it within one year. On any day, patients who were still engaged with the drug dosing regimen omitted about 10% of the scheduled doses: 42% of these omissions were of a single day’s dose, whereas 43% were part of a sequence of several days (three or more days—that is, drug “holidays”). Almost half of the patients had at least one drug holiday a year. The likelihood that a patient would discontinue treatment early was inversely related to the quality of his or her daily execution of the dosing regimen.Conclusions Early discontinuation of treatment and suboptimal daily execution of the prescribed regimens are the most common facets of poor adherence with once a day antihypertensive drug treatments. The shortfalls in drug exposure that these dosing errors create might be a common cause of low rates of blood pressure control and high variability in responses to prescribed antihypertensive drugs.